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1st Gen Ram Tech'93 & older Rams: This section is for TECHNICAL discussions only, that involve 1993 Rams and older. For any non-tech discussions, please direct your attention to the "General discussion/NON-tech" sub sections.
Sorry- I am not getting spark while cranking it over with the key. However with the OTC 4000e during the ignition test it is making a spark at the coil. I think something is preventing the computer from creating the spark, but I just am not sure what it is. In the manual there is a long list of things that could be wrong without sending a code. Still no codes, I'm not sure how to test the crank sensor but since this is the 3rd one I am thinking it may be okay.
i really don't know. you have pretty much replaced both sensors that could be causing a no spark issue. i would be wondering if it was either a wiring or computer issue since the computer can fire the coil but it just doesn't know when to do it.
Sorry- I am not getting spark while cranking it over with the key. However with the OTC 4000e during the ignition test it is making a spark at the coil. I think something is preventing the computer from creating the spark, but I just am not sure what it is. In the manual there is a long list of things that could be wrong without sending a code. Still no codes, I'm not sure how to test the crank sensor but since this is the 3rd one I am thinking it may be okay.
When did you last check your cap and rotor? I got a car towed in once that the rotor was fairly new but had a cracked rotor inside. Undr oressure from th center button, the metal tang had broken off.
The cap and rotor have a few hundred miles on them, but just to rule it out I put the old ones back on, no change. I did have the tip of a rotor fly off and kill the ignition on my 67 Dart during a pretty good burnout once.
Did you verify you have power to the coil during cranking? Asd relay working? If you have power then it's not getting a ground pulse from the pcm. Then you need to look at the cam/crank sensor inputs. That scanner is not going to do that along with most of them. You need a high end one that will graft it on the screen. It can be done with a meter but not as easy as looking at the screen.
No power to the coil while cranking but that video is super helpful, I am going to check the wires from the crank sensor and cam sensor and see if they are working correctly. Thank you.
After looking for over 6 months I finally found the truck I was looking for- a 1993 W150 short bed with a 5.9 Magnum engine. I found it in Northern California, went up there and drove it home to Los Angeles. No issues except bad gas milage. I replaced the battery terminals and put a ne Optima red battery in it, as well as oil change, new plugs, cap and rotor, air filter. It ran great for and I drove it daily, for about 4000 miles.
On a 100º day, I was driving it with the AC blasting and it was died at idle in an intersection. I pushed it into a parking lot as it would crank but not start. All the gauges worked and lights, but no spark. I left it there and went home to read the factory manual I bought when I got the truck. It sounded to me like the ASD relay, so I went and bought one and put it in. The truck started, and seemed fine. I drove it for another day when I was on the freeway blasting the AC again and it cut out at about 60 mph...pulled over and it cranked but wouldn't start.
While waiting for AAA on the phone, after 15 minutes on hold I tried to start it again, and it fired up. So I drove it off the freeway and went home. Figuring it was an issue with the air conditioning, I drove it a few more days with the AC off.
Then on the way home at night it died again, I pulled over and left it on the street overnight. The next day I went to get it and it started up, so I drove it home. I tried to see if there were any codes using the key method, and it had codes 11, 12, and 55. Code 11 is no signal at distributor so I replaced the camshaft sensor in the distributor. It fired up an ran great again.
I though it was fixed. Then I got to work and it died as soon as I parked it, would crank over but not start. I figured it's the crankshaft sensor which I did not want to change due to the lack of space in this one year only engine/frame combination.
I got a crankshaft sensor from Napa, (I think Standard made it), and changed it out. The truck fired up immediately, I reset the code, and now only was getting code 12 and 55.
It was running great and I thought I fixed it, went home, turned it off, and an hour later it wouldn't start. Cranks over, no start.
I put a fuel pressure gauge on the fuel rail port- 32psi as soon as you turn the key. I was 32psi 45 minutes later too. Not the fuel pump.
I was reading about the capacitors on the ECU circuit board going bad, so I ordered capacitors and replaced them on the board. I used to work with electronics so I'm pretty confident I did it right.
Put the ECU in, cranks, won't start.
Ordered a compatible ECU from ebay- mine is a CA only model, I got the 50 state model correct ecu rebuilt with warranty.
cranks over, won't start.
I tested the sensors, they are getting 5v, I am not getting power at the coil.
I checked the ASD relay, and it is getting power, and when cranked gets power to pin 87 for only a few seconds.
To say this is challenging is to put it lightly. I have looked at al the fusible links, no blown fuses, even looked at all the wiring behind the gauges...the wiring is as nice as can be for a 30 year old truck. There is zero rust anywhere on it and I don't think it has ever seen any bad weather or salt.
Basically what I am trying to find out here is if the crank sensor from Napa only worked for 6 miles, is that even possible?
Also would it throw a code or just not work? The pigtail on that thing is so short the only way I can test that sensor it is by removal.
I have read on this forum that the official Mopar sensor is what I should use, But I am at a loss.
I would probably drop it off at a shop if I thought they would do anything different than what I am doing.
Anyone who has some suggestions for me, please let me know. This truck is awesome but this problem is not.
Thanks! Dan
UPDATE: IT RUNS!
After looking at the schematics and tracing wires with my meter, I realized that the power was getting to the ignition switch but although it was cranking over it was not powering the ASD relay. I got an ignition switch from NAPA and installed it, now the relay has power and it starts and runs perfectly. The switch was original, but a few of the terminals were darker than the others and when I took it apart you can see the copper is oxidized.
The OBD1 has way less information than OBD2, and possibly is harder to troubleshoot than earlier systems. Anyway just for everyone's information-
The OTC scanner can test relays, injectors, and solenoids, but has no test for crank position sensor or cam sensor.
Also the ignition switch cranked over all the time, but the contacts inside were less than great so even though it seemed to work it turned out to be the problem,
The 1993 factory manual was helpful in this case but as with any intermittent problem, it takes some patience to track it down.
Hopefully this info will help someone who has this problem in the future.
I see a lot of threads where they never said what solved the problem. Thanks everyone for the suggestions and help.
Now I can get back to the bad gas milage and fun.
UPDATE: It wasn't fixed! It was the wiring!!!
After driving for a few days everything was great, then drove off a curb and it died. Lights on, everything working, cranking but no start. I shook the wiring near the distributor and it started. It's definitely a wiring issue. I figured I needed to be sure everything was good so I completely removed the wiring harness from the engine/trans.
It was shocking how many bad wires were in that harness!
Anyway since my chance of finding a new one is zero, I decided to fix this one. The crank position sensor connector is not visible when installed (you have to plug it in with one hand reaching up from underneath), but it was totally corroded and shorting from being twisted around.
Here are some photos
Anyway I wish I had done this sooner. The insulation on some of these wires had degraded, and I cut out sections and soldered in new wire. I reused the factory connectors and soldered new wire on to the terminals. Some of the damage I would have never been able to see if I had not taken the wiring harness out. Most of the destroyed wire was on the drivers side of the engine, close to the fuel rail test port...maybe gasoline got on the wires, who knows.
If you are having the same type of problems with this era Dodge, I highly suggest looking into the wiring in this area. Even though it was time consuming and a pain to reinstall, I am very happy I found the problem and the truck runs great once again.
I ended up replacing about ten sections of wire, about a foot long each. Most is 18ga but some is 16ga.
Hope this helps someone and be careful pulling the harness out, there are LOTS of connectors,
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